Fire extinguishing system and valve for use therewith

ABSTRACT

A fire extinguishing system and a valve for use therein, said system having both automatic and manual means for actuating the valve, said valve being designed for use in systems utilizing vaporizable extinguishants maintained under high pressure, and to give a very fast rate of extinguishant release, to allow the system to be used in applications where explosion suppression is desired. The valve is of the type utilizing a main valve and a pilot valve, in which the pilot valve is arranged to actuate the main valve by releasing the pressure on the back side thereof. In one embodiment of the invention pressure is supplied to the back side of the main valve piston only by leakage past the periphery of the piston. The pressure on the back side of the piston is released by the pilot valve to atmosphere rather than into the discharge line to avoid possible interference with said pressure release due to pressure buildup in the main discharge line. The pilot valve may be actuated by either a solenoid or mechanically by means contacting the face of the pilot valve covering the pilot valve discharge line, thereby avoiding sealing problems ordinarily encountered with such mechanical actuating means.

United States Patent [1 1 Tufts [111 3,788,400 ['45] Jan. 29, 1974 FIREEXTINGUISHING SYSTEM AND VALVE FOR USE THEREWITH [75] Inventor: HowardL. Tufts, Hingham, Mass.

[52] US. Cl 169/11, 169/22, 251/62 [51] Int. Cl. A62c 37/08 [58] Fieldof Search... 169/5, 11, 19, 20, 22; 251/62 [56] References Cited UNITEDSTATES PATENTS 9/1962 Williamson et al.... 169/11 11/1965 Hoevenaar169/5 X Primary Examiner-M. Henson Wood, Jr. Assistant Examiner-MichaelY. Mar Attorney, Agent, or FirmRobert E. Ross [57] ABSTRACT A fireextinguishing system and a valve for use therein,

said system having both automatic and manual means for actuating thevalve, said valve being designed for use in systems utilizingvaporizable extinguishants maintained under high pressure, and to give avery fast rate of extinguishant release, to allow the system to be usedin applications where explosion suppression is desired. The valve is ofthe type utilizing a main valve and a pilot valve, in which the pilotvalve is arranged to actuate the main valve by releasing the pressure onthe back side thereof. In one embodiment of the invention pressure issupplied to the back side of the main valve piston only by leakage pastthe periphery of the piston. The pressure on the back side of the pistonis released by the pilot valve to atmosphere rather than into thedischarge line to avoid possible interference with said pressure releasedue to pressure buildup in the main discharge line. The pilot valve maybe actuated by either a solenoid or mechanically by means contacting theface of the pilot valve covering the pilot valve discharge line, therebyavoiding sealing problems ordinarily encountered with such mechanicalactuating means.

6 Claims, 3 Drawing Figures FIRE EXTINGUISI'IING SYSTEM AND VALVE FORUSE THEREWITH BACKGROUND OF THE INVENTION Certain types of fireextinguishing systems utilize a container pressurized with a liquidextinguishant material and a discharge valve connected to the container,with means for automatically actuating said valve on the detection of afire, to release the extinguishant to discharge nozzles.

To achieve rapid release of the extinguishant on the receipt of a signalfrom the fire detecting device, a very fast acting valve is required,particularly in installations where the system is expected to act asexplosion supression means.

In such extinguishing systems it is customary to use a squib operatedvalve to achieve fast actuation, if the system is to be used as anexplosion suppression system. If not, a valve operated by a solenoidoperated pilot valve may be used. In this latter type of valve, a mainpiston is pressurized on both sides by the extinguishant, and maintainedclosed by the differential force resulting from the larger pressurizedarea on the back of the piston. The opening of a pilot valve releasesthe pressure from the back side of the piston into the discharge line,so that the pressure on the front side of the piston is utilized to openthe valve.

However commercially available valves of this type have been found to beinoperative when used with new types of extinguishants now available,apparently because of the high liquid to vapor expansion ration of suchmaterials, and the pressure at which they are stored. For example, a newextinguishant known commercially as Halon 1301, manufactured by E.I. duPont de Nemours Company of Wilmington, Delaware, has an expansion ratioof about 250 to l and is normally stored at a pressure of about 600p.s.i. When a material of this type is used with a valve of the typedescribed above, the valve does not operate satisfactorily to releasethe extinguishant at an adequate rate, due to valve chattering. This isapparently caused by the fact that when the valve is opened, the liquidextinguishant passing through the valve into the piping leading to thedischarge nozzles builds up sufficient pressure at the valve outlet tocause liquid extinguishant to back up into the chamber on the back sideof the valve through the pilot valve discharge line. This causes thepressure to again build up behind the main piston, forcing it closed.The problem is increased by the fact that liquid extinguishant alsoflows into the chamber on the back side of the valve through bleed orpressure equalizing orifices in the piston. The result is valve chatterthat reduces the rate of discharge of the extinguishant and renders thesystem ineffective for its intended purpose.

Another problem with such valves is the fact that even if the chatterproblem is eliminated in some manner, the speed of operation of thevalve is not great enough to allow it to be used in an explosionsuppression system. The speed of operation of the valve is apparentlyaffected by the fact that when pressure is released from the chamber onthe back side of the piston, pressurized extinguishant from the frontside of the piston (supplied directly from the pressurized container)passes through bleed holes in the piston and effectively reduces therate at which the pressure behind the piston can drop. Hence, for use inexplosion suppression systems, it has been necessary to usesquib-operated valves, which are susceptible to false firing and cannothave multiple firing capability.

A further problem with such valves is the fact that although means hasbeen provided for mechanically opening the valve to allow for manualfiring of the system, such means has required a high operating force toovercome the force holding the valve closed, and therefore themechanical advantage required for manual operation has ruled out the useof a simple pull cable operated from a distant control panel.

SUMMARY OF THE INVENTION In accordance with this invention a fireextinguishing system utilizes a valve in which a pilot valve dischargeport opens to the atmosphere rather than into the main discharge line,thereby preventing pressure in the discharge line after valve actuationfrom interfering with flow out of the pilot valve. Means is alsoprovided for restricting the rate of flow of liquid extinguishant intothe space behind the main piston to an amount less than the rate atwhich vaporized extinguishant can flow out of the pilot valve. Means isalso provided for mechanically unseating the pilot valve by means in thepilot valve discharge line pushing against the unpressurized face of thepilot valve covering the pilot valve discharge opening.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a view in section of a valveembodying the features of the invention.

FIG. 2 is an enlarged view of a portion of the valve of FIG. 1,illustrating the means for mechanically operating the pilot valve.

FIG. 3 is a schematic view of a fire detection and suppression systemutilizing the valve of FIG. 1.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENT Referring to FIG. 3 of thedrawing, there is illustrated a fire extinguishing system whichcomprises a bottle 10 containing a fire extinguishing medium underpressure, a valve 12 attached to the bottle, and a main discharge line14 leading to a series of discharge nozzles 16.

The valve 12 may be either manually actuated by a lever 18 orelectrically actuated by a solenoid 20 to release the extinguishant fromthe bottle to the nozzle 16, in a manner to appear hereinafter.Electrical actuation may be as a result of one or more of a plurality ofdetector units 22 actuating an amplifier 24 in response to radiationfrom a fire.

The valve 12 comprises a housing 26 with inlet and outlet 28 and 30, aninternal valve seat 32, a cylinder 34 formed above the seat, and apiston 36 slidable in the cylinder into and out engagement with the seat32.

A chamber 33 is disposed above the piston, and during standby operationof the fire detector system, the full bottle pressure exists on bothsides of the piston by means to be described hereinafter, so that thepiston, during such standby conditions, is forced tightly against thevalve seat due to the greater pressurized area on the top of the piston.A biasing spring 40 is provided between the piston and the upper portionof the housing to start the piston to the closed position after thevalve has been operated.

The valve is actuated by releasing the pressure from the chamber 36 bymeans of a pilot valve plunger 42 disposed in a housing 44. The housing44 opens to the chamber 38 so that the plunger 42 is surrounded by thechamber pressure. Spring 46 biases the plunger down onto a seat 48,which opens to a pilot valve discharge line 50 having a port 52 toatmosphere.

Mounted on the upper end of the housing 44 is the solenoid 20.Energization of the solenoid causes the plunger 42 to move upwardly,opening the chamber 38 to the atmosphere.

The pilot valve plunger 42 may also be lifted off its seat by the lever18 in a manner now to be described. Disposed at the bottom of thedischarge line below the port 52 is a camshaft 54 rotatable by the lever18 having a cam surface 56 formed thereon. Resting on the cam surface 56is a cam follower 58 which is movable vertically with rotation of thecam shaft by the lever 18. Protruding upwardly from the cam follower isa pin 60 which extends into the pilot valve seat opening and contactsthe bottom of the portion of the pilot valve covering the opening.Rotation of the camshaft by the lever moves the cam follower 58 and pin60 upwardly pushing the pilot valve plunger 42 up off of seat 48.

it has been necessary in valves of this type to provide small orificesin the piston 36 to allow the inlet pressure to bleed through to thechamber 38 to equalize the pressure on bothsides of the piston, so thatthe greater pressurized area on the chamber side of the piston will keepthe piston tightly seated. it is also customary to discharge thepressure from the chamber 38 into the main discharge line,

However, when a valve of this type, with the usual features as describedin the preceding paragraph, is used with a highly pressurized andrapidly vaporizing extinguishant such as the Halon 1301 mentionedpreviously, it has been found that severe valve chattering occurs, whichreduces the rate of flow of extinguishant through the valve to about onetenth of the desired rate. This is apparently due to the fact that whenthe valve opens and liquid extinguishant flows into the piping to thedischarge nozzles, the flow resistance causes the pressure to build upat the discharge outlet of the valve, causing liquid extinguishant toback up through the pilot valve discharge line and enter the chamber 38.At the same time the extinguishant under pressure passes as a liquidthrough the small pressure equalizing orifices in the piston, expands tovapor, which cannot get out because of the blockage of the pilot valvedischarge line. The resulting increase. in pressure in the chamber 38causes the valve piston to re-seat, shutting off the flow ofextinguishant through the discharge line. The above process then repeatsitself, casuing continuous valve chatter.

However, it has been found that with a valve having the structureillustrated, in which the pilot valve discharge line is vented toatmosphere and no pressure equalizing orifices are provided in thepiston 36, the valve operates satisfactorily with high pressure liquidextinguishants of the type previously mentioned, with no valvechattering, and adequate discharge rate. Although it would be expectedthat the lack of bleed oriflees in the piston would prevent theequalizing of pressure on both sides thereof, which would prevent thevalve from closing properly, it has been found that with this type ofextinguishant, sufficient leakage occurs between the piston peripheryand the cylinder wall to provide sufficient vapor pressure in thechamber to close the valve after the pilot valve is closed.

The omission of the equalizing orifices also increases the operatingspeed of the valve. Although for ordinary fires the difference of afraction of a second in valve operating time is of little significance,when the valve is used in a system which is expected to operate as anexplosion suppression device, maximum speed of valve opening on receiptof a signal from the detector is essential.

With no bleed orifices in the main piston, when the pilot valve opens todump pressure from the chamber 38, the rate of pressure drop in thechamber, and hence the rate of valve opening is greater in theillustrated device than if extinguishant were flowing into the chamberthrough equalizing orifices as the pilot valve is attempting to drop thepressure therein.

To operate as a system capable of suppressing an explosive type of fire,such as that produced by a spark ignited mixture of air and gasolinevapor, the extinguishant must be delivered by the system to surround theignited flame ball in 250 milliseconds or less, since after that timethe flame ball reaches such proportions that it is impractical tosurround by extinguishant, and the pressure in an enclosed compartmentresulting from the temperature rise of the burning gases becomes highenough to rupture the compartment walls.

In tests made on a valve of the general type illustrated with, however,the usual bleed orifices in the piston, the operating time from receiptof the signal from the detector amplifier to the solenoid to the time atwhich the valve is full open (as measured by the time of rupture of aseal over the valve discharge opening by the discharged extinguishant)is between and 130 milliseconds. Assuming an amplifier operating time of25 milliseconds from receipt by the detector of radiation from the flameball, only 95 to milliseconds are available for the extinguishant toflow through the piping and discharge from the nozzles. This amount oftime has been found to be inadequate.

However, when an identical valve as tested above is modified to thestructure illustrated and described herein, that is, with no bleed holesin the piston and the pilot valve discharging the chamber to atmosphere,the operating time, measured in the same manner, was between 9 and 14milliseconds. Hence the time available for the extinguishant to passthrough the piping and out of the nozzles is increased to between 21 land 216 milliseconds, which time has been found adequate to allow theextinguishant to surround and extinguish a flame ball before it reachesan uncontrollable size.

Since certain obvious changes may be made in the valve and extinguishingsystem described herein, it is intended that all matter contained hereinbe interpreted in an illustrative and not a limiting sense.

I claim:

1. A discharge valve for a fire extinguishing system of tyhe typeutilizing a container of vaporizible liquid under pressure, said valvehaving a seat and a piston closing the seat, said piston being slidablein a cylinder toward and away from the seat, the portion of the frontface of the piston around the seat being pressurized by the container,the chamber and the rear face of the piston being pressurized tomaintain the valve closed, means releasing the pressure from the chamberto actuate the valve, the means pressurizing the chamber being sodimensioned that the rate of flow of liquid extinguishant into thechamber when said means releasing the pressure from the chamber isactuated is less than the rate of flow of vaporized extinguishant out ofsaid means.

2. A discharge valve as set out in claim 1 in which the chamber ispressurized only by leakage of extinguishant between the periphery ofthe piston and the cylinder.

3. A discharge valve as set out in claim 2 in which said means releasingthe pressure of the chamber discharges the pressure of the chamber toatmosphere.

4. A discharge valve for use in a fire extinguishing system of the typeutilizing a container of vaporizable liquid under pressure, said valvecomprising a valve seat, a cylinder forming a chamber associated withsaid valve seat, a piston in the cylinder with its forward face normallycovering the valve seat and being movable away from the seat into thechamber to open the valve, v

line for lifting said plunger to open the discharge line and release thepressure from the chamber to open the valve.

5. A valve as set out in claim I in which said means in said dischargeline comprises a cam rotatable from outside the discharge line and a camfollower movable into and out of engagement with the face of saidplunger covering the discharge line.

6. A fire extinguishing system, comprising a container of vaporizableliquid extinguishant under pressure and a discharge valve connectedthereto, said valve comprising a main piston to open and close the maindischarge line, said main piston being normally pressurized on bothsides and an auxiliary piston normally closing a valve seat to anauxiliary discharge line, the opening of said auxiliary piston releasingpressure from one side of the main piston to allow said piston to openthe main discharge line, fire detector means, solenoid means responsiveto the detection of a fire by said detector means to lift said auxiliarypiston off its valve seat, and means in said auxiliary discharge linemanually operable from outside the discharge line to contact theauxiliary piston through the valve seat to lift said piston off of saidseat.

1. A discharge valve for a fire extinguishing system of tyhe typeutilizing a container of vaporizible liquid under pressure, said valvehaving a seat and a piston closing the seat, said piston being slidablein a cylinder toward and away from the seat, the portion of the frontface of the piston around the seat being pressurized by the container,the chamber and the rear face of the piston being pressurized tomaintain the valve closed, means releasing the pressure from the chamberto actuate the valve, the means pressurizing the chamber being sodimensioned that the rate of flow of liquid extinguishant into thechamber when said means releasing the pressure from the chamber isactuated is less than the rate of flow of vaporized extinguishant out ofsaid means.
 2. A discharge valve as set out in claim 1 in which thechamber is pressurized only by leakage of extinguishant between theperiphery of the piston and the cylinder.
 3. A discharge valve as setout in claim 2 in which said means releasing the pressure of the chamberdischarges the pressure of the chamber to atmosphere.
 4. A dischargevalve for use in a fire extinguishing system of the type utilizing acontainer of vaporizable liquid under pressure, said valve comprising avalve seat, a cylinder forming a chamber associated with said valveseat, a piston in the cylInder with its forward face normally coveringthe valve seat and being movable away from the seat into the chamber toopen the valve, the forward face of the piston around the seat beingnormally pressurized by the container, means pressurizing the chamber tothe same pressure as the forward face of the piston whereby the greaterpressurized area of the rear face of the piston maintains the pistonagainst the seat, a discharge line from the chamber and a plunger in thepressurized chamber normally covering the opening to the discharge line,means in said discharge line movable toward and away from theunpressurized portion of the plunger covering the discharge line forlifting said plunger to open the discharge line and release the pressurefrom the chamber to open the valve.
 5. A valve as set out in claim 1 inwhich said means in said discharge line comprises a cam rotatable fromoutside the discharge line and a cam follower movable into and out ofengagement with the face of said plunger covering the discharge line. 6.A fire extinguishing system, comprising a container of vaporizableliquid extinguishant under pressure and a discharge valve connectedthereto, said valve comprising a main piston to open and close the maindischarge line, said main piston being normally pressurized on bothsides and an auxiliary piston normally closing a valve seat to anauxiliary discharge line, the opening of said auxiliary piston releasingpressure from one side of the main piston to allow said piston to openthe main discharge line, fire detector means, solenoid means responsiveto the detection of a fire by said detector means to lift said auxiliarypiston off its valve seat, and means in said auxiliary discharge linemanually operable from outside the discharge line to contact theauxiliary piston through the valve seat to lift said piston off of saidseat.